1. Field
Example embodiments of the inventive concepts relate to semiconductor memory, and more particularly, to nonvolatile memory devices, reading methods thereof, and memory systems including the nonvolatile memory devices.
2. Description of the Related Art
A semiconductor memory device is a memory device that may be implemented with semiconductor materials, for example, silicon (Si), germanium (Ge), gallium arsenide (GaAs) and/or indium phosphide (InP). Semiconductor memory devices are largely categorized as volatile memory devices and/or nonvolatile memory devices.
A volatile memory device is a memory device in which stored data is erased when a power source is shut off. Volatile memory devices may include Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM) and/or Synchronous Dynamic Random Access Memory (SDRAM). A nonvolatile memory device is a memory device that retains stored data even when a power source is shut off. Nonvolatile memory devices may include Read-Only Memory (ROM), Programmable Read Only Memory (PROM), Erasable Programmable Read Only Memory (EPROM), Electrical Erasable Programmable Read Only Memory (EEPROM), flash memory, Phase-change Random Access Memory (PRAM), Magnetoresistive Random Access Memory (MRAM), Resistive Random Access Memory (RRAM) and/or Ferroelectric Random Access Memory (FRAM). A flash memory device is largely categorized into NOR type and/or NAND type.
A three dimensional 3D array structure in which memory cells are vertically stacked may enhance a degree of integration of semiconductor memory devices.